INVESTIGATION OF STRAIN-DEPENDENT MAGNETIC BARKHAUSEN NOISE IN STEEL

Angular dependent magnetic Barkhausen noise (MBN) measurements were pe rformed on three pipeline steel samples under uniaxial tensile stress up to 260 MPa. An expression for the angular dependent strain given by delta L/L approximate to Delta L/L (1-(1+nu)sin(2) theta), where thet a is the angle of the strain component with respect to the maximum str ain Delta L/L was compared with the results. It was observed that the MBN signal was greater for the magnetic sweep field aligned along dire ctions of greater tensile strain. Results were interpreted in terms of the relative increase of the active 180 degrees domain wall populatio n in the direction of the applied magnetic field and in the sense of i ncreasing tensile strain.